1. Field of the Invention
The present invention relates to a substrate provided with a super-absorbent material, to a method for the manufacture thereof, a method for manufacturing the super-absorbent material, in addition to the use of the substrate in different products.
2. Description of the Related Art
Super-absorbent materials used for a variety of applications have existed for decades. Such super-absorbent materials are capable of binding a multiple of their own weight in liquid, particularly water, sometimes up to five hundred times as much.
The super-absorbent capacity of such materials is based on swelling. The materials are at least partially cross-linked polymer chains containing a large number of COOH groups. Through contact with water or an aqueous liquid hydrogen atoms will split off and COO− groups will be formed. These negatively charged carboxylate groups repulse each other, whereby the cross-linked polymer forms a three-dimensional network, in which the water molecules are as it were captured. The water molecules are held in the super-absorbent material by means of hydrogen bridges. The (partial) cross-linking of the material is essential for the effectiveness thereof, since “separate” polymer chains would simply dissolve in the liquid instead of absorbing it.
Super-absorbent materials occur as powders or fibers. The advantage of powders is that they have a markedly higher absorption capacity than fibers due to their significantly larger surface area. Super-absorbent fibers are moreover more expensive.
Powders are usually applied to a substrate, which in turn is further processed into the end product. In particular cases powders are also directly processed. The great drawback of powder however is that it causes dusting and dust nuisance both in the manufacture of substrates coated with powder and in the processing of those substrates or the loose powders themselves. Dust nuisance is not only very unpleasant but also causes loss of material and therefore waste and is moreover bad for the health of those working with the powders.
It is therefore the object of the present invention to provide a substrate provided with a super-absorbent material which does not have the above stated drawbacks.